1. Technical Field
The present invention relates to an imaging device, and in particular to technology for correcting an influence of physical motion of the imaging device on a captured image.
2. Background Art
Among imaging devices, a wearable camera is a camera that is anticipated to be continually worn by a wearer, and to be continually imaging. By continually recording images, wearable cameras are expected to be effectively utilized for aiding recall of human memory, etc. (for example, see Patent Literature 1).
Since this type of wearable camera is anticipated to be continually used, in cases such as when the wearer is moving vigorously or when the camera is not firmly fixed to the wearer, the camera shakes irregularly. The video captured when the camera is swaying in this way also shakes irregularly.
Since shaky videos are likely to cause dizziness and a feeling of discomfort called “video induced motion sickness” in users, correcting and removing the shakiness from the video is necessary.
One method for removing shakiness uses a motion vector. Since the calculation load is large when searching from one end of an image to the other for motion vector detection, there is conventional technology for setting a window, as a search range, in one portion of the image.
The smaller the window, the more the calculation load can be reduced, but when the physical motion of the camera is great, there is a possibility that the resulting motion vector of the image cannot be detected. Nonetheless, setting a large window leads to an increase in the calculation load necessary for the search. In this way, there is a trade-off relationship between the size of the window and the calculation load.
Related to this, there is technology (Patent Literature 2) that, by changing an image capturing frame rate to a higher value when the motion vector between frame images is large, can handle even large motions while decreasing the relative amount of motion between frames and suppressing the size of the window to a constant (Patent Literature 2).